// [1763]最长的美好子字符串
struct Solution;

//leetcode submit region begin(Prohibit modification and deletion)
impl Solution {
    pub fn longest_nice_substring(s: String) -> String {
        let mut ans = "".to_string();
        // 定义窗口状态为
        ans
    }
}
//leetcode submit region end(Prohibit modification and deletion)


#[test]
fn main() {
    let s = "YazaAay".to_string();
    assert_eq!(Solution::longest_nice_substring(s), "aAa".to_string());
    let s = "Bb".to_string();
    assert_eq!(Solution::longest_nice_substring(s), "Bb".to_string());
    let s = "c".to_string();
    assert_eq!(Solution::longest_nice_substring(s), "".to_string());
    let s = "dDzeE".to_string();
    assert_eq!(Solution::longest_nice_substring(s), "dD".to_string());
}